A sample of 16 high redshift quasars with 2.4⪉ z⪉ 3.8 was observed with moderate spectral resolution in the restframe ultraviolet. The emission-line fluxes of NV1240, CIV1549, and HeII1640 were used to estimate the elemental abundance of the line emitting gas. The line ratios were investigated within the frame work of models presented by Hamann & Ferland (1992, 1993, 1999). The scaled solar abundance model yields inconsistent results for the metallicity while the rapid star formation scenario is more successful in indicating a common range of overabundance on base of NV1240/CIV1549 and NV1240/HeII1640 line ratios. We estimated a metallicity of Z = 8 Zsun of the line emitting gas given by NV/CIV and NV/HeII. Assuming an evolution time scale of 1 Gyr and a cosmological model with Ω M = 0.3, Ω Λ = 0.7, and Ho = 65 km s-1 Mpc-1 the first violent star formation epoch should start at a redshift of zf = 6 to 10. I have benefited from support from SFB328, SFB439 (Landessternwarte Heidelberg, FRG), DFG grant Ko 857/13-1 (Universitätssternwarte Göttingen, FRG), and NASA grant NAG 5-3234.
American Astronomical Society Meeting Abstracts #195
- Pub Date:
- May 2000